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Current time:0:00Total duration:2:59

Video transcript

- [Voiceover] Traveler's diarrhea is caused by a bacteria known as enterotoxigenic E. coli. It's often referred to as Montezuma's Revenge if contracted in Mexico and as Delhi Belly if contracted in India. The bacteria itself is usually transmitted via the fecal to oral route. That is, you may eat some kind of food or drink some water that's been contaminated with feces and that feces was contaminated with the pathogen. Once you ingest this pathogen, it'll make its way past the stomach and into the small intestine. So like always, we're gonna focus on this green layer over here, known as the epithelium. We'll focus in on one of those epithelial cells. The bacteria will look something like this and it'll actually try to physically associate with the epithelial cell using the structures known as pili, which is just plural for pilus. Once it's associated with the epithelial cell, it'll release two different types of toxins to help it enter that cell. The first is known as heat-labile enterotoxin and the second is known as heat-stable enterotoxin. Heat-labile just basically means that this enterotoxin is going to be inactivated at high temperatures. Heat-stable means that this enterotoxin will be stable at high temperatures. So eventually these enterotoxins will help the bacteria enter the epithelial cell. Once the bacteria is in the epithelial cell however, it'll continue to release those enterotoxins. These enterotoxins will then act on different enzymatic pathways and biochemical signaling pathways. But they'll have the same end result. They'll cause the secretion of water and chloride, and in addition, they'll prevent the reabsorption of sodium. So what you're doing is you're actually squeezing the contents of the epithelial cell out into the lumen of the small intestine. Notice this is actually a pretty similar mechanism to the way that the cholera toxin works. In fact the heat-labile enterotoxin acts on the same enzymatic pathway that the cholera toxin does. When this bacteria enters your system, it'll cause all sorts of different symptoms, much like the other forms of gastroenteritis. Usually the symptoms start within hours after exposure and it lasts for about a few days. Given that the bacteria operates similarly to cholera, a lot of the symptoms will be similar. This includes profuse watery diarrhea, dehydration, and like all other forms of gastroenteritis you may experience some nausea and vomiting. You may also experience some cramps in your abdomen. If you go to the doctor, like always, they're going to order a stool sample. That stool sample will be evaluated for its contents and if they see that you have the enterotoxigenic E. coli, then there's a good chance that you have traveler's diarrhea. There aren't really that many treatments explicitly for traveler's diarrhea, except to drink a lot of water. Remember that your small intestine is actually expelling the water from its own system, so you're going to be experiencing a lot of dehydration. If you want to prevent getting traveler's diarrhea while you're traveling, the best thing to do is to drink bottled water or really just any water that you know for sure is clean because in doing so you could avoid the risk of drinking some water that's been contaminated with the pathogen.